Porous Carbon Oxide Nanocomposite Electrodes for High Energy Density Supercapacitors

Abstract

A high energy density supercapacitor is provided by using nanocomposite electrodes having an electrically conductive carbon network having a surface area greater than 2,000 m²/g and a pseudo-capacitive metal oxide such as MnO₂. The conductive carbon network is incorporated into a porous metal oxide structure to introduce sufficient electricity conductivity so that the bulk of metal oxide is utilized for charge storage, and/or the surface of the conductive carbon network is decorated with metal oxide to increase the surface area and amount of pseudo-capacitive metal oxide in the nanocomposite electrode for charge storage.

Description

CROSS REFERENCE TO RELATED APPLICATION [0001]This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61 / 232,831, filed Aug. 11, 2009 entitled, POROUS GRAPHENE OXIDE NANOCOMPOSITE ELECTRODES FOR HIGH ENERGY DENSITY SUPERCAPACITORS.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to carbon-oxide nanocomposite electrodes for a supercapacitor having both high power density and high energy density.[0004]2. Description of Related Art[0005]During the past two decades, the demand for the storage of electrical energy has increased significantly in the areas of portable, transportation, and load-leveling and central backup applications. The present electrochemical energy storage systems are simply too costly to penetrate major new markets. Still higher performance is required, and environmentally acceptable materials are preferred. Transformational changes in electrical energy storage science and tec...

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Benefits of technology

[0024]Graphene is a planar sheet 19 of carbon atoms 20 densely packed in a honeycomb crystal lattice, as later illustrated in FIG. 6, generally one carbon atom thick. It has an extremely high surface area of greater than 2,000 m2/g, preferably from about 2,000 m2/g to about 3,000 m2/g, usually 2,500 m2/g to 2,000 m2/g and conducts electricity better than silver. MnO2 has a high capacitance due to additional bulk participation for energy storage (MnO2+K+ (potassium ion)+e−=MnOOK). The graphine can be substituted for by activated carbon, amorphous carbon and carbon nanotube and the MnO2 substituted for by NiO, RuO2, SrO2, SrRuO3.

[0025]In this invention, newly designed nanocomposite electrodes allow employment of increasing amount of the pseudo-capacitive oxide by directly sup

Problems solved by technology

The present electrochemical energy storage systems are simply too costly to penetrate major new markets.

NiMH batteries were the initial workhorse for electronic devices such as computers and cell phones, but they have almost been completely displaced from that market by lithium-ion batteries because of the latter's higher energy storage capacity.

Today, NiMH technology is the principal battery used in hybrid electric vehicles, but

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